HIGH BODY MASS INDEX AND REDUCTION OF RESPONSE TO RITUXIMAB IN PATIENTS WITH RHEUMATOID ARTHRITIS

Adipose tissue has immunomodulating effects in rheumatoid arthritis (RA). Previous studies suggested that obesity could negatively affect the response to anti-TNF-α agents. We aimed to determine whether body mass index (BMI) is involved in the response to the anti-CD20 “Rituximab” in RA. In 100 patients with active RA, the BMI was categorized into two groups (<25 kg/m² and ≥ 25 kg/m²) and calculated before initiation of rituximab treatment. Changes from baseline in Disease Activity Score in 28 joints (DAS28); Health Assessment Questionnaire (HAQ) disability index; C-reactive protein levels (CRP); erythrocyte sedimentation rate levels (ESR); tender and swollen joint count (TJC, SJC); pain and global on a visual analog scale (VAS) were analyzed within 12 weeks. The primary outcome was decreased in DAS28 ≥ 1.2, while secondary outcomes were the European League against Rheumatism (EULAR) response criteria. Radiographical erosive status and adipokine levels of pigment epithelium-derived factor (PEDF) and chemerin were also evaluated. As a result, the mean ± SD of BMI for all patients was 27 ± 4.6 kg/m². The BMI correlated positively with the DAS28 at baseline (r=0.42, P<0.05). Alterations in the disease activity components were associated with a change in the HAQ, TJC, and VAS of pain and global. According to the EULAR response criteria, BMI values were significantly higher in the non-responder, compared with the good responder group (P<0.05). In the heavier RA patients, erosive status was less, while adipokine levels of PEDF and chemerin were more. In conclusion, RA patients with a high BMI responded less well to rituximab.